Researchers in Austria have discovered that females are much better than males at noticing when a tennis ball rolling behind a wall appears to change size. In fact, males don't seem to notice at all. Don't worry, guys--I'm talking about dogs.
Corsin Müller and his colleagues studied 25 male dogs and 25 female dogs. Each dog was led into a room by its owner and allowed to play with a large and a small blue tennis ball; this let the dogs get familiar with the objects in the experiment. Then the owners walked the dogs out of the room and back in again. Owners sat in a chair--blindfolded, so as not to give any inadvertent clues to their pets--and sat their dogs between their knees. Meanwhile, a hidden experimenter watched the dog with a camera. When the dog was calmly looking in the direction of a low wall, the experiment ...
